[ARC5] BC-453 B dynamotor hum

[Kenneth G. Gordon]

On 1 Nov 2015 at 16:42, J Mcvey wrote:

> I just tried changing the 12A6-same problem!

Well, we thought it might be. Nice to confirm that though.

> It would have been nice if I found some output transformers, too. Anybody got
> one to sell? 

Probably not, although maybe someone does. I did see some Italian fellow 
on eBay who was selling one or two for something like $50.00 each. You 
might also ask Fair Radio Sales directly. They still have some NIB never 
used ARC-5 receiver parts, but they will have to go look at their stash, and 
as far as I know, there is only one fellow who knows where the stuff is and 
who will look for it. He found me some 239 kc BFO transformers in that pile, 
all NIB.

Also, be aware that there were at least three different transformers 
depending on the exact model of your receiver. However, any will work in 
any receiver.

Is your receiver a museum or collector-quality receiver?

If it is not, then you might consider a standard small 70 Volt line-transformer. 
Radio Shack used to carry those, and transformers like them are available 
on eBay.

Proper connection will result in a near perfect match to the output of the 
12A6, but output impedances will be 8 or 16 ohms.

The big problem with those is that there are only a few ways to mount them 
without drilling holes (God forbid!!!!!). Glueing them in place with some 
super-glue will work, if the receivers aren't bounced around afterwards.

All the above, of course, assumes that the problem you are having actually 
IS the audio output transformer. We have not yet established that....

Ken W7EKB